Approach to Aquatic Skin Infections

Approach
to Aquatic
Skin
Infections
Abdullatif Sami Al Rashed
Clinical Microbiology Resident
King Fahd Hospital of The University
27/1/2021
1

Objective
• To discuss the common etiologic agents associated with salt-
and fresh-water skin and soft tissue infections, approach for
detection and evidence-based management.
2

Outlines
• Introduction
• Epidemiology
• Risk Factors
• Cases
• References
3

Introduction
Vasagar B, Jain V, Germinario A, Watson HJ, Ouzts M, Presutti RJ, Alvarez S. Approach to aquatic skin infections. Primary Care:
Clinics in Office Practice. 2018 Sep 1;45(3):555-66.
Aquatic-based SSI can present a treatment challenge for primary care physicians because
of the likely polymicrobial nature of the infection and the possibility of uncommon
pathogenic organisms.
Although Staphylococcus and Streptococcus species that colonize the skin are the
most common etiologic agents associated with salt water and freshwater infections,
other significant pathogens are known to cause these types of infections.
The microbiology depends on the type of water exposure as well as individual patient
factors.
5

Epidemiology
• The epidemiology of bacterial infections following aquatic injuries has not been
intensively and widely investigated.
• The risk of soft tissue infection due to traumatic injury with water exposure may be
considered in the following hierarchy:
• Fresh water (ponds, small lakes)
• Flowing fresh water (rivers, large lakes)
• Brackish water
• Sea water
• Well-regulated treated swimming pools, hot tubs
Czachor JS. Unusual aspects of bacterial water-borne illnesses. Am Fam Physician. 1992 Sep;46(3):797-804. PMID: 1514473.
6

Risk Factors
Recreational
swimmers
Rescue
workers
Fisherman
Boaters
Flooding
victims
Czachor JS. Unusual aspects of bacterial water-borne illnesses. Am Fam Physician. 1992 Sep;46(3):797-804. PMID: 1514473.
7

https://www.uptodate.com/contents/soft-tissue-infections-following-water-
exposure?search=water%20exposure&source=search_result&selectedTitle=1~150&usage_type=default&display_rank=1
8

Case 1
‘‘my legs are hurting’’
Kumamoto KS, Vukich DJ. Clinical infections of Vibrio vulnificus: a case report and review of the literature. The Journal of emergency medicine. 1998 Jan 1;16(1):61-6.
9

Case 1
• A 45-year-old male with a history of end-stage liver disease
(secondary to ethanol abuse and hepatitis C infection)
presented to the ED with the chief complaint of ‘‘my legs are
hurting’’ for 1 day.
• The pain was described as a sudden onset of an intense
burning sensation from both feet to the upper thighs, equal in
intensity bilaterally. The patient denied any trauma.
10

Case 1
• The pain started the night before and was associated with a
high fever (39.4°C oral), vomiting, and dyspnea in the
morning.
• He had no complaints of chills, nausea, cough, diarrhea,
dysuria, abdominal pain, or chest pain.
11

Case 1
• On examination, the patient had a temperature of 37.8°C oral, pulse
of 121 beats/min, respirations 24 breaths/min, and blood pressure of
100/63 mmHg.
• He was alert and oriented but was in moderate distress secondary to
pain.
• No scleral icterus was noted. Cardiac and pulmonary examinations
were normal. The abdomen was minimally obese, had decreased
bowel sounds, was soft, non-tender to palpation, and without
evidence of hepatosplenomegaly, masses, or ascites.
12

Case 1
• The lower extremities were moderately swollen in appearance
bilaterally from the feet to the thighs with nonpitting edema.
• No trauma was noted except for mild abrasions on the anterior
aspects of the shins. There were no rashes or erythema noted. The
lower extremities were exquisitely tender to palpation but were not hot
to touch.
• Pulses were equal bilaterally, capillary refill was poor, and no cords or
local lymph nodes were palpable. There were no focal neurological
deficits as touch and pinprick sensations, deep tendon reflexes, and
strength were equal and intact bilaterally
13

Let’s discuss the possibilites
14

Infectious Non-infectious
Cellulitis Deep venous thrombosis
Necrotizing fasciitis Contact dermatitis
erysipelas Acute gout
Toxic shock syndrome Vasculitis
Gas gangrene Insect bite
myonecrosis Panniculitis
Erythema migrans
Herpes zoster
Septic arthritis
Skin abscess
DDx of leg pain
Stevens DL, Bisno AL, Chambers HF, et al. Practice guidelines for the diagnosis and management of skin and soft tissue infections:
2014 update by the Infectious Diseases Society of America. Clin Infect Dis 2014; 59:e10. 15

Case 1
• CBC showed:
• WBC 3,500/mm3 , hemoglobin 14.9 g/dL, hematocrit 35.2%, MCV 102.8, platelets 15,000 with
46% neutrophils, 48% band forms, 2% lymphocytes, 2% monocytes, and 2% myelocytes.
• Sodium was 131 mmol/ liter, potassium 3.8 mmol/liter, chloride 102 mmol/liter,
bicarbonate 16.4 mmol/liter, blood urea nitrogen 24 mg/ dL, creatinine 2.3 mg/dL,
and glucose 99 mg/dL.
• Amylase was 55 U/dL and lipase 148 U/liter.
• PT/PTT was 19.6 s/37.9 s with an INR of 2.9. The arterial blood gas was pH 7.463,
pCO2 20.7 mmHg, pO2 72.8 mmHg, and O2 saturation 96% (room air).
16

Case 1
• The patient’s chest radiograph and electrocardiogram were normal.
17

Case 1
• Initial diagnostic evaluation was directed toward ruling out a vascular
source for the patient’s lower extremity condition.
• A lower extremity duplex ultrasound was obtained to evaluate the
possibility of a deep venous thrombosis (DVT) causing the lower extremity
symptoms; the scan showed obstruction of the superficial saphenous veins
of the right thigh but was negative for DVT.
• Abdominal ultrasound revealed no evidence of abdominal aortic aneurysm
18

Case 1
• During the course of evaluation, the patient developed a microvascular
petechial rash on the lower extremities and clinical thought turned toward
the possibility of an evolving vasculitis or septicemia from cellulitis.
• Intravenous steroids and broad spectrum antibiotics (ceftriaxone,
vancomycin, gentamycin, and metronidazole) were given empirically.
19

Case 1
• The d-dimer and fibrin split product assays were high and a low fibrinogen
level (71 mg/dL) was found.
• He was given platelets and fresh frozen plasma for treatment of
disseminated intravascular coagulation (DIC).
• The creatine phosphokinase was 11,323 IU/liter, suggesting that
rhabdomyolysis was occurring. There was no evidence of myocardial
infarction.
20

Case 1
• During the evaluation the patient became diaphoretic, tachypneic, hypoxic,
and his mental status deteriorated, requiring rapid sequence induction and
endotracheal intubation.
• He became hypotensive; resuscitation with crystalloid and dopamine was
begun.
What could be the causes ?
As a microbiologist, what do you recommend and why?
21

Case 1
• The lower extremity lesions progressed to blanching, macular lesions and
then to dark, fluid-filled bullous lesions.
• It was learned that the patient had consumed raw oysters 2 days before
presentation in the ED.
22

Case 1
• The patient’s labile blood pressure required epinephrine for stabilization.
• Doxycycline was started for empiric coverage of V. vulnificus infection.
• The following afternoon the patient became hypotensive, went into
pulseless electrical activity (PEA), and was successfully resuscitated.
• However, 2 h later he again went into PEA and progressed to asystole.
Thirty-six hours after checking into the ED triage desk, the patient was
pronounced dead.
• Blood cultures and fluid from the bullous wound cultures grew V. vulnificus.
23

Vibrio vulnificus
infection
24

V.vulnificus
• V. vulnificus exists as a free-living bacterium inhabiting
estuarine or marine environments.
• Cases peak during summer and late fall, when water
temperatures are highest.
• Filter-feeding shellfish such as oysters concentrate bacteria
and may have counts of V. vulnificus up to two orders of
magnitude greater than those in the surrounding water.
25

V.vulnificus
• Wound infections generally result from exposure of a wound
to salt or brackish water containing the organism, and most
often occur in the setting of handling seafood or in
association with recreational water activities
26

V.vulnificus
• Individuals with the following conditions are at increased risk for serious
infection with V. vulnificus
• Alcoholic cirrhosis (present in 31 to 43 percent of patients with primary septicemia)
• Underlying liver disease including cirrhosis and chronic hepatitis (24 to 31 percent
of patients)
• Alcohol abuse without documented liver disease (12 to 27 percent of patients)
• Hereditary hemochromatosis (12 percent of patients)
• Chronic diseases such as diabetes mellitus, rheumatoid arthritis, thalassemia
major, chronic renal failure, and lymphoma (7 to 8 percent of patients)
27

Virulance factors
• Virulence of V. vulnificus has been associated with a variety
of potential factors:
(1) production of an anti-phagocytic polysaccharide capsule;
(2) MARTX and other toxins; and
(3) iron availability and iron acquisition systems
28
Do you know why ?

Courtesy of Glenn Morris Jr, MD, MPH&TM.
Graphic 63423 Version 5.0, uptodate
• V. vulnificus causes Rapidly progressive SSI,
incubation period 3-7d
• SSTIs caused by V vulnificus have three clinical
stages: initially inflammatory, followed by bullous,
and finally gangrenous.
• The fatality rate for wound infections ranges from
20 to 30%.
• Primary septicemia has a fatality rate exceeding
50%, even with hospitalization
Alert: Very serious infection!
29

Close up of colonies of Vibrio vulnificus, strain VV100, cultivated on bovine blood agar during 24 h at
37°. The total length of the scale bar is equivalent to 5 mm.
Credit: Karel Krovacek (BVF, SLU) & Karl-Erik Johansson (BVF, SLU & SVA).
Colonies of Vibrio vulnificus, strain VV100, cultivated on bovine blood agar
during 24 h at 37°. Note the hemolysis around the colonies.
Credit: Karel Krovacek (BVF, SLU) & Karl-Erik Johansson (BVF, SLU & SVA).
30

Colonies of Vibrio vulnificus, strain VV100, cultivated on
TCBS cholera agar during 24 h at 37°.
Credit: Karel Krovacek (BVF, SLU) & Karl-Erik Johansson
(BVF, SLU & SVA).
85% green
15% yellow
31

Which of the following statement is correct?
1. Vibrio vulnificus is facultatively anaerobic curved gram-negative
bacilli, motile, catalase and oxidase positive, can’t grow on 42 C, VP
negative and ferment glucose and maltose.
2. Vibrio vulnificus is facultatively anaerobic curved gram-negative
bacilli, non motile, catalase positive and oxidase negative, can grow
on 42 C, and doesn’t ferment glucose and maltose.
3. Vibrio vulnificus is strict anaerobic curved gram-negative bacilli,
motile, catalase and oxidase positive, can’t grow on 42 C, VP
negative and ferment glucose and maltose.
32

Treatment
• Patients with septicemia or serious wound infections using
combination therapy with either:
• Minocycline or doxycycline (100 mg orally twice daily), plus
either cefotaxime (2 g intravenously every eight hours) or ceftriaxone (1 g
intravenously daily);
• Doses should be appropriately adjusted for underlying renal or hepatic disease.
• The combination of cefotaxime and ciprofloxacin is also likely effective.
• Fluoroquinolone monotherapy (ie, levofloxacin 750 mg orally or
intravenously once daily) is another alternative.
Uptodate recommendations
33

Treatment
• Serious wound infections may require aggressive debridement in
addition to parenteral antibiotics.
• Mild wound infections in patients who do not have significant
underlying diseases generally respond well to local care and oral
antibiotics (such as a tetracycline or a fluoroquinolone).
• Duration of therapy is dictated by severity of the initial infection
and clinical response; patients with mild to moderate infections
generally respond to five to seven days of antibiotics.
Uptodate recommendations
34

Case 2
”mud football game nightmare”
Vally H, Whittle A, Cameron S, Dowse GK, Watson T. Outbreak of Aeromonas hydrophila wound infections associated with mud football. Clinical infectious diseases. 2004 Apr 15;38(8):1084-9.
36

Case 2
• On Sunday, 17 February 2002, a total of 26 persons who had
participated in a charity mud football competition in Collie on the
previous day presented to the emergency department at Collie
Hospital with infected scratches and pustules over their torsos and
limbs.
• Most persons reported 20–30 lesions, with some reporting 1100
lesions.
• One patient required removal of an infected thumbnail at the
emergency department, and another required surgical debridement
of an infected toe in the hospital the next day.
37

Case 2
• The games were played between 1:30 pm and 4:00 pm in the
afternoon on a mid-summer day in which the maximum
temperature reached 26 C.
• Two football fields were used simultaneously with each game
consisting of two 15-min halves.
38

Case 2
• All 26 patients (or their parents) who presented to the emergency department
at Collie Hospital on Sunday, 17 February, were interviewed.
• A questionnaire was used for the interview that addressed the clinical
features and exposure of the patients to mud and to river water.
• Other data collected included the estimated number and location of skin
lesions, other presenting symptoms, preexisting medical conditions, and
current systemic antibiotic treatment.
39

Vally H, Whittle A, Cameron S, Dowse GK, Watson
T. Outbreak of Aeromonas hydrophila wound
infections associated with mud football. Clinical
infectious diseases. 2004 Apr 15;38(8):1084-9.
40

Case 2
• Most patients were reported to have bathed in the river after
playing in the mud; however, many patients also showered
with river water before bathing in the river
41

Case 2
• Swab samples of skin lesions and debridement tissues were
plated onto horse blood agar plates.
• After overnight incubation at 35C, oxidase-positive GNB
colonies were isolated.
• Further identified with the API 20E biochemical identification
system (BioMerieux) identified A. hydrophila.
42

Epidemiology
• Aeromonads are inhabitants of aquatic ecosystems, such as groundwater,
reservoirs, and clean or polluted lakes and rivers, worldwide.
• The majority of studies have found a seasonal relationship between the
recovery of aeromonads from specimens and the warmer months of the year
• Since Aeromonas is not a reportable condition in the United States or in most
other countries, the true incidence of Aeromonas infections worldwide is not
known.
• Estimates from England/Wales and the United States for septicemia with aeromonads
in 2004 revealed an incidence of 1.5 per million population
Manual of clinical microbiology. 11th edition.
43

Direct gram stain of skin or superfecial samples?
• The direct microscopic examination of wound or skin/superficial
specimens or positive blood culture specimens somewhat
unremarkable in that aeromonads appear as straight, Gram-negative
bacilli, with or without the presence of white cells,
• Which look like the presentation of a similar infection with either enterics or
pseudomonads.
44

• Aeromonas spp are oxidase-positive,
polar flagellated, glucose-fermenting,
facultatively anaerobic, gram-negative
rods that are resistant to the
vibriostatic agent O/129 and unable to
grow in 6.5 percent NaCl.
• String test negative
45

Closely Related Species ?
Test Aeromonas spp Pleismonas spp
DNASE
Oranthine
Lysine
decarboxylase
Arganine
Test Aeromonas spp Vibrio spp
O/129
Vibriostatic agent
String test
Grow in >6%
NaCL
+ -
+
-
- +
- +
Resistant Sensitive
- +
- +
46

MALDI-TOF MS Performance in Identification?
• MALDI-TOF MS have excellent performance for identifying
aeromonads to the genus level.
• However, it has limitations in identifiying aeromonads to the
species level.
• Vitkek MS has acknolwedged that the system currently:
1. Doesn’t properly discriminate A.caviae from A.hydrophilia
2. Frequently fails to identify A. veronii strains
47

Case 2
• Antibiotic susceptibility testing of clinical isolates was completed using
the agar dilution method.
• These isolates were found to be resistant to amoxicillin, meropenem,
oral cephalosporins (cefaclor and cephalexin), cephalothin, and colistin
and were susceptible to norfloxacin, ciprofloxacin, gentamicin,
tobramycin, amikacin, trimethoprim, ceftriaxone, ceftazidime,
amoxicillin–clavulanate potassium, ticarcillin disodium–clavulanate
potassium, aztreonam, cefepime, and nitrofurantoin
48

Aeromonas spp AST
• There are CLSI testing guidelines for the major clinical Aeromonas
species that relate to antimicrobial dilution and disk susceptibility
testing in document M45-A2 for infrequently isolated or fastidious
bacteria
• Aeromonas species can express three chromosomal β- lactam-
induced β-lactamases, including:
• Group 1 molecular class C cephalosporinase,
• Group 2d molecular class D penicillinase, and
• Group 3 molecular class B metallo-β- lactamase (carbapenemase).
49

51

Case 2
• Public health inspection of the mud football fields, the
adjacent Collie River, and the irrigation equipment was
performed by the local environmental health officer.
• In addition, a water sample was obtained from the river near
the inlet pipe for the irrigation pump and tested for
temperature, pH, and bacterial pathogens.
52

Case 2
• To test water samples for Aeromonas species, 100 mL of
water was filtered through a 0.45-mm nitrocellulose
membrane.
• This membrane was then placed on a horse blood agar plate
containing ampicillin (5 mg/L). After incubation overnight at
37C, oxidase-positive GNB colonies were further identified
with the API 20E biochemical identification system as
A.hydrophilia.
53

• Incubation period 1-2d
• Often follows wounds sustained when filleting
fish
• Causes ring-shaped lesion with a sharply
demarcated purplish/red border, associated with
intense pain (erysipeloid)
• May mimic septic arthritis or result in
disseminated endocarditis.
Erysipelothrix rhusiopathiae
Courtesy of DermNet New Zealand (http://www.dermnetnz.org/topics/erysipeloid/) and the Waikato District Health Board (http://www.waikatodhb.health.nz/).
• Indolent infection, mean incubation period 21
days).
• Cleaning salt water aquariums and crustacean
puncture during seafood preparation.
• Usually appear as papules or nodules on an
extremity (especially on the elbows, knees, and
dorsum of feet and hands); subsequently, they
progress to shallow ulceration and scar formation
• Most lesions are solitary; occasionally
"ascending" lesions develop with "sporotrichoid
spread”.
Reproduced with permission from: www.visualdx.com. Copyright VisualDx. All rights reserved.
Graphic 81640 Version 5.0
M. marinum
56

References
• Vasagar B, Jain V, Germinario A, Watson HJ, Ouzts M, Presutti RJ, Alvarez S. Approach to aquatic skin
infections. Primary Care: Clinics in Office Practice. 2018 Sep 1;45(3):555-66.
• Vally H, Whittle A, Cameron S, Dowse GK, Watson T. Outbreak of Aeromonas hydrophila wound infections
associated with mud football. Clinical infectious diseases. 2004 Apr 15;38(8):1084-9
• Kumamoto KS, Vukich DJ. Clinical infections of Vibrio vulnificus: a case report and review of the literature.
The Journal of emergency medicine. 1998 Jan 1;16(1):61-6.
• Manual of clinical microbiology. 11th & 12th edition.
• Uptodate
• CLSI M45
57

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